Rock drill



J.' C. CURTIS Jan. 6, 1942.

ROCK DRILL QE N .ANN

jmm, i w@ a w ,H J. w iwUH E A @1 1 v u r w Jan. 6, 1942. J. cuRTls ROCK DRILL A Filed May 5, 1938 Patented Jan. 6, 1942 ROCK DRILL John C. Curtis, Claremont, N. H., assigner to Sullivan Machinery Company, a corporation of Massachusetts Application May 5 1938, Serial No. 206,193

8 Claims.

This invention relates to rock drills, and more particularly, but not exclusively, to improvements in the supporting and guiding structurel and the associated feeding mechanism of a hammer rock drill whereby the drill hammer motor is supported, guided and fed in an'improved manner.

An object of this invention is to provide an improved supporting and guiding structure for a hammer rock drill. Another object is to provide an improved rock drill feeding mechanism. Still another object is to provide an improved automatic feeding mechanism operated by a vibratory action set up within the drill hammer motor during operation of the latter for effecting drill feed. Yet another object is to provide an improved recoil resisting or checking means associated with the drill hammer motor for controlling the feeding movement of the latter. A further object is to provide an improved automatic vibration-controlled drill feeding 'mechanism having embodied therein improved 'reversible control means whereby the drill hammer motor may be fed selectively iin opposite directions along the drill guide. A further object is to provide an improved automatic vibrationcontrolled feeding mechanism for .a lhammer 'rock drill wherein a sliding carriage mounted on a drill guide carries a ratchet-controlled, feed control sprocket engaging a relatively stationary chain secured to the drill guide. Still another object is to provide improved means for guiding the control cha-in with respect to the control sprocket whereby more than tangential operative engagement of the chain and sprocket .is attained. Other objects and ladvantages of the invention will, however, hereinafter more fully appear in the course of the following vdescription and as more particularly `pointed out in' the appended claims.

In the accompanying drawings there is shown for purposes of illustration one form which the invention may assume in practice.

In these drawings:

Fig. 1 is a view in longitudinal vertical section, with parts shown in side elevation, through a hammer rock drill constructed in accordance with an illustrative embodiment of the invention.

Fig. 2 is a longitudinally extending horizontal sectional view, with parts shown in plan, taken substantially on line 2--2 of Fig. 1, the drill hammer motor being removed and a portion of the trunnion support structure broken away to facilitate illustration.

Fig. 3 is a rear end elevational view of the Aimproved rock drill.

Fig. 4 is an enlarged cross sectional View taken substantially on line 4--4 of Fig. 1.

Fig. 5 is an enlarged 'cross :sectional view taken substantially on line 5-5 tof Fig. 1.

Fig. 6 is a detail sectional view' taken on line 6 6 of Fig. 5. Y

Fig. 7 is a detail sectionalview taken online 7 1 of Fig. 5. I Y

Fig. 8 is a detail sectional View taken von line 8-3 of Fig. 5. y

Fig 9 is an enlarged detail sectional view taken on line 9-9 of Fig. 2.

Fig. 10 is a detail sectional view' taken on line In this illustrative embodiment 4of the invention, the drill supporting andl guiding structure, generally designated I, andthe associated feeding mechanism, generally designatedk 2, are shown embodied in a rock drill of the mounted hammer type, and in this instance, the feeding mechanism is operated and controlled by a vibratory action set up within va drill hammer motor, generally designated 3, during operation ofthe latter. It will be `evident, however, that various features of the vinvention maybe embodied in tools of various other types.

The drill hammer rmotor -3 is herein of a conventional design comprising a motor cylinder 4 having front and back heads '5 and 6 and conhammer motor 'of the type disclosed 'is well known vto those skilled inthe art, further description 'of the structure and mode of operation thereof is herein considered unnecessary.

Now referring to the drill supporting and guiding structure I, it will be noted `that an elongated drill guide Iii, in the form of a bar and of generally T-shaped cross section, has lateral top flanges I 5, I5 and an upright bottom flange I6 arranged perpendicular to the plane of the top flanges, the bottom flange I6 having a polygonal bottom portion I'I shaped for reception in .a 'visey like lclamp I8. This clamp comprises a clamping jaw 'I9 formed on a horizontal trunnion sup'- port 28 having at the side thereof oppositeirom said clamp a vertically disposed swivel plate 2| adapted to be clamped in the conventional truni` nion clamp of a saddle mounting.` Cooperating with the stationary clamp' jaw I9 is 'a movable clamping jaw 22` (Fig. 4.)., and aY bolt 23 is mounted in a bore in the trunn-ion support and has threaded thereon an adjusting nut 2d engaging the clamp 22 for adjusting the latter.V

When the clamp is loosened, the drill guide bar I4 may be slid longitudinally into different positions with respect to the trunnion support and thereafter rigidly clamped in position on the trunnion support by tightening the clamping jaw 22. The polygonal bottom portion I'I of the guide has relatively inclined sides adapted to fit' within opposed conical seats and 26, in the clamp members I8 and 22, respectively, so that when the clamp is tightened, the drill guide is held rigidly in position both against longitudinal movement and lateral displacement with respect to the `trunnion support.

The improved automatic drill feeding mechanism 2 associated with the drill supporting and guiding structure, comprises a sliding carriage frame having bottom guideways 3| receiving the lateral flanges I5, I5 of the drill guide bar I4, so that the carriage is mounted on the drill guide bar for sliding movement longitudinally therealong. The carriage frame 30 is in the form of a casing and is provided with an internal chamber 32 Within which a feed control means is arranged. Arranged in the casing' chamber is a horizontal shaft 33 suitably journaled in ball bearings and having an integral chain sprocket 34, as shown in Fig. 5.- Keyed to the shaft 33 is a sleeve-like hub 35 of a rotatable ratchet ring 36, the latter having internal ratchet teeth 31. Arranged concentrically within the ratchet ring 36 is a stationary pawl carrier 38 (Fig. 5) having a'stub shaft 39 keyed to a detachable cover plate 40 of the carriage casing. This pawl carrier carries reversible spring-pressed pawls 4I and 42 (Fig. `6) engageable with the ratchet teeth 31, to controlthe direction `of rotation of the chain sprocket 34. The pawls are herein preferably eight in number, four for controlling the direction `of rotation of the sprocket 34 in one direction `and four for controlling the direction of rotation of the sprocket in the opposite direction. For selectively rendering the sets of pawls 4I and 42 effective, a shifter annulus 43 is rotatably mounted within the casing bore on a circular projection 44 of the cover plate 40, and this annulus has recesses 45 (Fig. '7) to permit the pawls to move into engagement with the ratchet teeth, and an internal surface 46 of the guide bar.

`vcontrol chain is secured at 5S to an adjusting bar I4, and the latter has an upstanding ledgelike projection 5B extending longitudinally along the top surface thereof and with which the chain engages for guiding the chain to maintain the chain in longitudinal alinement with the drill As illustrated, the rear end of the screw extending through an opening in a bracket 6I secured to the rear end of the drill guide` I4. Threaded on the screw and engaging the Opposite 'sides' of the bracket are adjusting and locking nuts 62 for adjusting the screw 60 to vary thev tension of the control chain. As shown most clearly in Fig. 9, the forward end of the chain is secured at 63 to an upstanding projection 64 integral with the forward end of thev drill guide bar I4.

The universal connection between the drill hammer motor and the sliding carriage 30 comprises a yoke-shaped frame B5 swivelly mounted at 66 on a vertical axis on the sliding carriage to swing horizontally with respect thereto in planes parallel to the plane of the drill guide bar. The yoke-shaped frame is pivotally mounted on a pin B1 arranged in alined bores on the carriage frame, and this pin has a grasping knob 68 whereby, the pin may be `axially released from the carriage frame, thereby to enable detachment of the yoke-shaped frame G5 from its pivotal connection with the carriage frame. The arms 59 of the yoke-shaped frame have alined openings for receiving a horizontal bolt 'I0 mounted in a transverse bore 'I I lin the rear head 6 of the drill hammer motor. The drill hammer motor is pivotally mounted on the bolt I0 for swinging movement in a vertical direction with respect to the sliding carriage and drill guide. It will be seen that the pivot pin I'IA and bolt I cooperate to provide a universal pivotal connection between the rear end of the hammer motor 3 and the sliding carriage 30.

tachable frame 'I2 having guideways 'I3 slidably annulus is engageable with the pawls for pressing the latter inwardly into their released position. For moving the shifter annulus 43 into its different positions, a lever 41 (Fig. 8) projects within 'a slot 48 in the annulus, and this lever is secured to a control shaft 49 rotatably mounted 34, as shown in Fig. 1, engages a feed control' chain 55, and guide rollers 5B journaled on horizontal shafts 5'I supported by the carriage casing guide the hchain through the open bottom of the carriage frame and relative to the chain sprocket. The guide rollers are arranged with respect to the control sprocket to direct the chain partly around the sprocket so that more than tangential' operative engagement therebetween is attained. The control chain 55 lies on the top of and extends longitudinally along the drill guide 0' embrace the drill steel.

engageable with the top flanges I5, -I5 of the guide bar I4 at the forward end of the latter. The centralizer frame I2 has upstanding hookshaped guiding fingers or lugs Madapted to The centralizer frame may be secured to the drill guide bar I4 by a transverse bolt 'I5 insertible through openings in the frame 'I2 and engageable with a transverse groove 16 in the projection 64. When the 'centralizer is in the position shown in Figs. 1

and 9, the hook-shaped portions of the guiding fingers I4 engage the opposite sides of the drill steel to hold the latter against lateral displacement and for supporting the forward end of the drill hammer motor during spotting of a hole. The centralizer may be readily detached from the drill guide bar I4 simply by removing the bolt 'I5 and sliding 'the frame 'I2 forwardly from the guide bar flanges I5, the lugs or fingers 'I4 being disposed in opposed relation and spaced a suiiicient distance apart so that when the centralizer frame is turned and thereafter moved laterally, the centralizer may be released from the drill steel.

The mode of operation of the improved rock drill is as follows: The drill guide bar" I4 may be set up at the working face by clamping the swivel plate 2| of the trunnion support 20 .in the trunnion clamp of a saddle mounting, and the guide bar may be adjusted longitudinally with respect to the work by loosening the clamp I8, and when in proper position `may thereafter be firmly clamped in place. When the drill guide bar is in the desired location, the drill steel centrahzer is placed with its guiding fingers 'I4 in proper guiding relation with respect to the drill steel I9 and attached by the bolt I5 to the forward end of the drill guide bar I4, in the manner shown in Fig. 1. The operator may then manipulate the throttle valve mechanism I3 to effect the supply of motive iluid to the drill hammer motor 3, to actuate percussively the drill steel. When the drill hammer motor is running to effect percussive actuation of the drill steel I0, the reciprocatory movement of the hammer piston 'I causes, due to the sudden reversal in the direction of movement of the piston, vibratory or recoil movements of the hammer motor alternately in opposite directions longitudinally thereof, as is well understood by those skilled in the art; resulting in alternating tendencies of movement of the hammer motor forwardly and rearwardly with respect to the drill guide bar. Movement of the hammer motor in the direction opposite to that in which it is desired to effect feed is checked automatically by the ratchet and pawl mechanism, the active pawls 4l engaging the ratchet teeth 3l, automatically checking reverse movement of the hammer motor and freely slipping relative to the ratchet teeth, automatically to permit movement of the hammer motor in the feeding direction. When the shifter annulus 43 is in the position shown in Fig. 7, the control sprocket 34 is free to rotate in ya counter-clockwise direction as viewed in Fig. 1, relative to the control chain 55, thereby permitting forward movement of the drill hammer motor along the drill guide bar I4, the control chain, as the hammer motor moves forwardly, effecting such counter-clockwise rotation of the control sprocket. Reverse rotation of the control sprocket is checked automatically by the pawls 4I engaging the teeth of the ratchet ring 36, and as a result, rotation of the sprocket in a clockwise direction 'as viewed in Fig. 1, is prevented. It will thus be seen that as the hammer piston I of the hammer motor reciprocates within the hammer motor cylinder 4 to actuate percussively the drill steel lo, the jars imparted by the hammer piston, due to the sudden reversal in the direction of movement thereof, cause the hammer motor to jump step by step in Va forward direction along the drill guide bar I4, thereby feeding the drill steel toward the work. When spotting of the drill hole is completed, the drill steel centralizer is, of course, detached from the drill steel and guide bar. When the operator manipulates the handle 53, the shifter annulus 43 may be rotated to effect release of the pawls 4I, shown in Fig. '7, and to permit the pawls 42 to move into engagement with the teeth of the ratchet ring 36, When the parts are in this reversed position, the control sprocket 34, as viewed in Fig. l, is free to rotate in a clockwise direction, so that as the hammer piston rapidly reciprocates within the hammer motor cylinder the control sprocket is free to rotate in a reverse feeding direction relative to the control chain, due to the jars set up by the hammer piston, the active pawls 42 releasing automatically to permit free rotation of the control sprocket in the reverse feeding direction, as the hammer motor moves rearwardly along the drill guide bar, and holding automatically the control sprocket against rotation in the opposite direction, i. e. :a :counter-clockwise Ldirection .as viewed in Fig. l. When vthe shifter annulus 43 is lmoved into its intermediate position, both sets of `pawls 4I, 42 are free to engage the ratchet teeth; and as a result, Vthe Acontrol sprocket 34 is locked against rotation in vboth directions, so that movement of t-he hammer motor along the drill guide bar is prevented. Due to the universal connection of the rear end of the drill hammer motor with the sliding carriage of the automatic feed, the hammer motor may be swung in av vertical direction relative to the drill guide bar into different angularly related drilling positions, as indicated in dotted lines in Fig. 1, and may be swung laterally relative to the ydrill guide bar into different angularly related drilling positions, as indicated in Vdotted lines in Fig. =2,; and 'in any of these inclined drilling positions, the automatic feed is effective to feed the drill steel toward or from the work; it being understood that the front end of the hammer motor is supported at that time by engagement of the drill steel with the Work. The drill holes drilled by the hammer motor in these relatively incl-ined positions are, however, of a relatively shallow depth, due to the gradual lchange in inclination of the drill steel as the sliding carriage of the automatic feeding means moves longitudinally along `the drill guide bar. VThe main purpose, however, of the universal pivotal connection between the hammer motor and the sliding carriage is -to permit the drilling of straight holes even when the drill steel HJ is bent or otherwise out of alinement.

As a result of this invention, it will be noted that an improved rock drill is provided Yhaving an improved vsupporting and guiding structure for the drill hammer motor and im-proved automatic feeding mechanism for feeding the hammer motor along th-e guide structure. It will further be noted that an improved drill feeding mechanism is provided which is yoperated and controlled by a vibratory action set up within the drill hammer motor during operation of the latter. It will still further be noted th'at by the provision ofthe improved control means of the chain and sprocket type and the novel arrangement of the chain sprocket and control chain, an automatic drill feed of an extremely simple and compact ycha-racter is obtained. It will also be noted that by the provision of the universal pivotal connection between the drill hammer motor and the sliding carriage of the drill feeding means, holes may be drilled in relatively inclined positions with respect to the drill guide. It will further be noted that the improved rock drill is not 'only compact and rugged in construction, but is also relatively simple Vand inexpensive in design. Other uses and advantages of the improved rock drill will be clearly apparent to those skilled in the art.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other fo-rms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure b Letters Patent is:

1. In a drillingapparatus, the combination with a support, of a motor slidable on the support and having jars .imparted thereto, and 'a recoil resisting vmechanism for said motor including a sprocket wheel rotatably carried by the motor and a chain carried by the support and held against longitudinal movement relative thereto, said chain passing partly around said sprocket Wheel in operative engagement therewith, stop means for preventing the rotation of said sprocket Wheel in one direction to enable a step by step longitudinal movement of the motor in one direction, and means carried by the motor and engaging th'e chain for guiding the latter partly around said sprocket Wheel.

2. In a drilling apparatus, the combination with a support, of a motor slidable on the support and having jars imparted thereto, and a recoil checking mechanism for said motor including a flexible element secured to the support against longitudinal movement relative thereto, a rotatable member carried by the motor and engaging said element for rotation due to the jars imparted to the motor, stop means for preventing the rotation of said member in one-direction to enable a step by step feeding motion of the motor, and means carried by the motor and engaging said flexible element for effecting lateral displacement of the latter to the support during the feeding motion of the motor.

3. In a drilling apparatus, th`e combination with a support, of a motor slidable on'the support and having jars imparted thereto, and a recoil resisting mechanism for said motor including a chain extending longitudinally of the support and secured thereto against longitudinal movement, a sprocket Wheel rotatably carried by the motor in operative engagement with the chain, said sprocket wheel having a radial thrust irnparted thereto due to its engagement with said chain tending to move the sprocket Wh'eel away from the chain, stop means for preventing the rotation of said sprocket wheel in one direction torenable a step by step longitudinal movement of the motor in one direction, and means carried by the motor and engaging said chain for counterbalancing said radial thrust.

4. In a drilling apparatus, the combination with a support, of a motor slidable on the support and having jars imparted thereto, and a recoil resisting mechanism for said motor including an elongated element extending longitudinally of the support and formed with traction means, a member rotatably carried by the motor in operative engagement with thetraction means (of said element, said member having a radial thrust imparted thereto due to its operative engagement with said traction means, stop means for preventing the rotation of said member in one direction to enable a step by step feeding motion of the motor, and means carried by the motor and engaging said elongated element for counterbalancing the radial thrust imparted to said member.

5. In a drilling apparatus, the combination with a support, of a motor slidable on the support and having jars imparted thereto, and a recoil resisting mechanism for said motor including a chain extending longitudinally of the support, a sprocket wheel carried by the motor in operative engagement with said chain, stop means for preventing the rotation of said sprocket wheel in one direction to enable a step by step feeding motion of the motor, and means carried by the motor and guiding said chain into more than tangential operative engagement with said sprocket wheel.

6. In a rock drill, the combination comprising a guide, a hammer motor guided for movement along said guide and in which longitudinal vibratory movements in o-pposite directions occur during running of the motor, and means operated by said longitudinal vibratory movements for effecting feed of said hammer motor along said guide comprising a flexible element secured at its ends to said guide, a rotatable control member mounted on said guide for movement relative thereto with said hammer motor and engaging said flexible element so that the vibrations setup within said motor effect rotation of said control member, stop means for preventing rotation of said control member in one direction to enable step by step feeding motion of said motor, and means mounted on said guide to move relative thereto with said motor and engaging said flexible element at the opposite sides of said control member for effecting guiding of said flexible element into more than tangential operative engagement with said control member.

7. In a rock drill, the combination comprising a guide, a hammer motor in which longitudinal vibratory movements in opposite directions occur during running of the motor, said motor mounted on said guide for movement therealong, and means operated by said longitudinal vibratory movements for effecting feed of said hammer motor along said guide comprising a flexible element secured to said guide, a rotatable control member disposed on a transverse axis and mounted on said guide for movement relative thereto with said hammer motor, said control member engaging said flexible element so that the vibrations set up Within said motor effect rotation of said control member, stop means for preventing rotation of said control member in one direction to enable step by step feeding motion of said motor, and means comprising a pair of rotatable guides disposed on opposite sides of said control member on axes parallel to the axis of rotation of said control member for effecting guiding of said flexible element into more than tangential operative engagement with said control member.

8. In a rockdrill, the combination comprising a guide, a hammer motor in which longitudinal vibratory movements in opposite directions occur during running of the motor, said motor mounted on said guide for movement therealong, and means operated by said longitudinal vibratory movements for effecting feed of said hammer motor along said guide comprising a flexible element secured to said guide, a rotatable control member disposed on a transverse axis and mounted on said guide for movement relative thereto with said hammer motor, said control member engaging said flexible element so that the vibrations set up Within said motor effect rotation of said control member, stop means for preventing rotation of said control member in one direction to enable step by step feeding motion of' said motor, and means comprising a pair of rotatable guides disposed on opposite sides of said control member on axes parallel to the axis of rotation of said control member for effecting guiding of said flexible element into more than tangential operative engagement with said control member, said axes of said rotatable guides lying in a longitudinal plane parallel to the plane of said guide and the axis of rotation of said control member being disposed in a plane parallel to said plane.

J. C. CURTIS. 

